1. Field of the Invention
The present invention relates to an imaging control system for controlling an imaging apparatus, an apparatus and a method for controlling the imaging apparatus, and a storage medium.
2. Description of the Related Art
A conventional imaging control system includes an imaging apparatus connected to a network and a client apparatus which controls the imaging apparatus via the network. The imaging control system can control panning and tilting drive mechanisms of the imaging apparatus through operations on the client apparatus. A known imaging control system is directed, when driving an imaging apparatus for panning and tilting, to making it easier for a user to orient the imaging apparatus in the direction of a target object (for example, Japanese Patent Application Laid-Open No. 2004-266876). The imaging control system stores in a memory of an imaging apparatus a table for setting a relation between the panning angle and name display characters such as “North”, “South”, “East”, and “West.” The imaging control system orients the imaging apparatus to a panning angle corresponding to a name display character input by a user, and displays on a monitor the name display character corresponding to the direction to which the imaging apparatus is oriented.
A known method displays buttons for indicating the panning and tilting directions at predetermined positions around a captured image (for example, Japanese Patent Application Laid-Open No. 4-373386 and Japanese Patent Application Laid-Open No. 8-237533). However, there has been a case where the conventional method cannot suitably show a user the imaging direction since the panning and tilting directions dynamically change in response to operations of the panning, tilting, and rotation mechanisms.
As a method for assisting the user to orient the imaging direction of the imaging apparatus to a target direction when driving the imaging apparatus for panning and tilting, the panning and tilting drive directions may be possibly superimposed onto the captured image, as illustrated in FIG. 9A. When the user changes the imaging direction of the imaging apparatus to the panning or tilting direction, the method illustrated in FIG. 9A superimposes onto the captured image as direction guides 913 and 914 a moving path to be traced by an imaging center 911 which is an intersection of a plane containing the captured image and an optical axis 901 of the imaging apparatus. However, when superimposing the panning and tilting drive directions, there arises a problem that the user cannot recognize the panning and tilting drive directions in a specific imaging direction in some cases.
A problem arising in drive direction display will be described below. Modes for displaying the drive direction on a display image and a change in panning direction display accompanying the operation of the tilting mechanism will be described below with reference to FIGS. 9A and 9B.
Referring to FIG. 9A, the optical axis 901 denotes an imaging direction of an imaging apparatus, a display image 910 denotes an image displayed on a display apparatus, an imaging center 911 denotes a center of the captured image, and a panning rotation center 912 denotes the position of a panning rotation center on the display image 910. Referring to FIG. 9A, a panning direction guide 913 is a panning direction guide for indicating the panning drive direction by the panning drive mechanism, and a tilting direction guide 914 is a tilting direction guide for indicating the tilting drive direction by the tilting drive mechanism. Each of the panning direction guide 913 and the tilting direction guide 914 is represented by a straight line or curve passing through the imaging center 911. Each of the direction guides 913 and 914 dynamically changes in shape with the changing imaging direction, i.e., according to operations of the panning, tilting, and rotation mechanisms.
As illustrated in FIG. 9A, the closer the optical axis 901 is to the perpendicular to the panning rotational axis 203, the straighter the panning direction guide 913 and the smaller its curvature. FIG. 9B illustrates a display image 920 produced when the tilting mechanism is operated from the state of the optical axis 901 to bring the imaging direction close to the panning rotational axis 203. As illustrated in FIG. 9B, the closer the imaging direction is to the panning rotational axis 203, the shorter the distance between the imaging center 911 and the panning rotation center 912 and the larger the curvature of the panning direction guide 913 on the display image 920. When the imaging direction is close to the panning rotational axis 203, the panning direction guide 913 forms a circle or arc having a small radius, making it difficult for the user to recognize the panning drive direction. If the imaging apparatus 110 continues the tilting operation from the above-mentioned state, the panning direction guide 913 converges to a point and can no longer be displayed when the imaging direction coincides with the panning rotational axis 203. In this state, the user cannot recognize the panning drive direction.
As mentioned above, when the panning direction guide 913 and the tilting direction guide 914 are superimposed onto the captured image such that these direction guides pass through the center of the captured image, it becomes difficult or impossible for the user to recognize the panning moving direction. In this state, the user may be confused when attempting to adjust the orientation of the imaging apparatus 110 with a desired imaging direction.